Topic: Coils, wires, caps... it's all too much!

[B.O.X.N.I.F.E.]

did a search, mind is oficially boggled.

Just got Dyna 5 ohm coils. Adding to a Dyna III ignition on my 550. Currently have stock coils with resistor caps.

For these new coils do I need:

- Copper core or suppression wires?
- Resistor or non resistor caps?

[Jerry Rxman Griffin aka MuthaF'er]

I'm running 7mm copper core wires without the resistor cap on my Dyna III and 3ohm coils. Fires like a mofo! Why limit the juice when I spent all that cash to get hotter sparks?!

[B.O.X.N.I.F.E.]

Are you using resistor plugs since you got rid of the caps?

[TwoTired]

The resistors or resistance wires do not limit the spark gap voltage!  There is resistance to make the spark event broader and longer lasting during the event, and also to limit excessive currents that can advance the spark erosion of the electrodes, which shortens spark plug life.

You should have resistance in either spark plugs, the spark caps or the resistance wire.   But, you should choose only 1 of these options.

A) Resistor plugs, non-resistor plug caps, solid core wire.
B) Non-resistor plugs, Resistor Plug caps, solid core wire.
C) Non-resistor plugs, non-resistor Plug caps, suppression wire.

Suppression wire has a shorter useful life than solid core wire.  The core deteriorates with age.
If your plug caps currently have resistors and are in good condition,  I'd choose "B".

Cheers,

[B.O.X.N.I.F.E.]

Awesome, TT, as always.

Two more quick q's

The stock caps are resistor caps, right?

NGK D7ea's are non resistor plugs?

[TwoTired]

The stock plug caps are usually either 5K or 10K.  Usually the 750's have the former and the 550's have the latter.  I'm not exactly  sure why, though.

Th NGK caps can also be found with no resistors in them.  Butm Honda didn't use those on stock bikes, AFAIK.

Resistor plugs nearly always have an R in the number somewhere.  DR7EA would be resistor types, D7EA is non-resistor.

Cheers,

[B.O.X.N.I.F.E.]

The stock plug caps are usually either 5K or 10K.  Usually the 750's have the former and the 550's have the latter.  I'm not exactly  sure why, though.

Th NGK caps can also be found with no resistors in them.  Butm Honda didn't use those on stock bikes, AFAIK.

Resistor plugs nearly always have an R in the number somewhere.  DR7EA would be resistor types, D7EA is non-resistor.

Cheers,

I got the whole setup yesterday and noticed they sent 5k caps. I have a 550, and according to Z1 these caps came up under the model search for my bike. Should I go with it or are 10k caps critical?

[tomsweb1]

Th NGK caps can also be found with no resistors in them.  Butm Honda didn't use those on stock bikes, AFAIK.

Canadian 750s used DR8ESL plugs and non-resistor caps.

[B.O.X.N.I.F.E.]

Just wanted to bump this as I've had some electrical weirdness going on.

Will these 5k resistor caps be ok on the 550, which apparently is 10k in stock configuration?

[TwoTired]

What do you mean, "ok".  Will they allow spark?  Yes.  Should you use them with non resistor plugs?  Yes.

[TwoTired]

Th NGK caps can also be found with no resistors in them.  Butm Honda didn't use those on stock bikes, AFAIK.

Canadian 750s used DR8ESL plugs and non-resistor caps.

Ah yes.  Now I remember reading about the Canadian variant.  I never found one of those in California. (Not that I really looked, mind you.) I wonder if that change must be removed as it crosses the border to the US and Vice versa?   

[B.O.X.N.I.F.E.]

What do you mean, "ok".  Will they allow spark?  Yes.  Should you use them with non resistor plugs?  Yes.

I thought you indicated the 550's came with 10k resistor caps, and the 5k was designated to the 750's.

Z1 sent 5k's which I am now using on a 550.

[Achmed]

I just checked mine today on the 750 F1 and they measured between 8K and 10K ohms. I believe the coils (and wires) are stock.

[TwoTired]

What do you mean, "ok".  Will they allow spark?  Yes.  Should you use them with non resistor plugs?  Yes.

I thought you indicated the 550's came with 10k resistor caps, and the 5k was designated to the 750's.

Z1 sent 5k's which I am now using on a 550.

All the factory 550's I've checked had 10K caps.  750's typically have 5K caps.  I also told you I didn't know exactly why.  In theory, the higher resistance should give it a broader spark with slightly less secondary current.  This may lead to less power usage from the coil, aiding overall power consumption.  Possibly the higher resistance may help reduce the electrode spark erosion from the hotter spark plugs used on the 550.
These bikes also had stock coils which were wound and cored quite differently from the dyna replacements you have.

I don't really know why Z1 sent you 5K caps, unless they only had stock of 5K caps.  Or, maybe they didn't imagine you'd care about 550 power conservation, spark plug longevity, etc., which the Dyna III is unlikely to help with in any case. (I'm assuming it will have far longer dwell time to hold the coil saturated far longer than the stock points system provided.  Since add blurb says: "DYNA III Electronic Ignition increases the high rpm coil energy storage by approximately 70%!")

I don't think you will break anything using the 5K resistors.  But, as you now have mostly Dyna components, you should follow what recommendations or specifications they have for your set up.  Call them.  You are a customer.  They have customer support.

Cheers,

[B.O.X.N.I.F.E.]

You're definetly right, I need to give Dyna a call, I've got almost all their ignition stuff on the bike now. I actually didn't mind stock coils, and the bike gave me less problems with them, possibly a coincidence. The fixed wires are why I got rid of them, mine were in awful shape with cracking all over. I found the Dyna's for 79$ on ebay!

I wish Z1 would indicate what resistance each cap has. I'll give them a call as well, they've been very helpful before.

Tonight I had the tank off on the road side (out of gas, thought it might be coils problem  )

The coils felt warm to the touch. Not hot, but defineteley warm. Is this normal? The heat felt as if it were generated by the coil, seemed too warm to just be engine proximity.

Thanks TT!

[TwoTired]

When a 5 ohm coil is powered, it draws 33 watts (about) and expends this power as heat.

I have 3 -  750s/btw.  They all had 5k ohm caps.  One of them sat parked since 1984 -ish.  It had one bad cap when I got it running again, replaced it with 5kohm to match the others.

All the 550's in my collection have 10K ohm caps.  It would be a very odd coincidence that all my 500/550 examples from 72 to 78 had their plug caps changed to non-stock.

I think I hear (The Twilight Zone Theme     ).

It's fun to tell stories on the forum.

[B.O.X.N.I.F.E.]

I wasn't doubting you! If Dyna says to put 10k's on there, I'll get them from Honda and see if Z1 would take them back or I can pass them on to a 750'er. I'll let ya'll know what Dyna says.